Reciprocating knives have been widely accepted in industry and in the home as labor-saving devices which enable the user to easily and accurately cut meat, bread and other edible and inedible materials. Power reciprocating knives have been particularly useful to the meatcutting industry where production is highly dependent upon the speed with which meat can be cut. Solenoid operated and gear driven knives are known to the art, but the complexity of their designs makes them difficult to assemble and repair. Solenoid knives may also be susceptible to electric shortcircuiting when used in a moist environment. A reciprocating knife which is efficient, accurate and readily assembled and repaired is disclosed in U.S. Pat. No. 3,283,407 issued to Bacon, one of the inventors of the improvements hereinafter described. The Bacon knife uses a rotatably mounted, elongated drive shaft with an inclined cam plate affixed thereon to drive a track-guided knife blade by positioning the edge of the inclined cam within a blade opening and rotating the cam such that the blade reciprocates in accordance with the varying position of the cam edge. This knife has numerous advantages for use and maintenance. It is reasonably inexpensive to manufacture and assemble; it may be used while completely immersed in water; and it may easily be cleaned after use. Should the cam or blade become excessively worn, each can be easily replaced without excessive delay.
The Bacon knife would typically be constructed with some play between the cam edge and the rim of the blade opening. Moreover, as the cam and the rim become worn with use, the amount of play between them increases. While such wear may not appreciably affect the operability of the knife, such play does cause noticeable vibrations as the blade reaches the forward and rearward extents of its stroke. Moreover, there will be a corresponding noise produced as the rim of the blade opening hits against the cam surface. Eventually, blade replacement may become necessary. In addition, wear of the cutting edge during use of the knife can make blade sharpening or at least temporary blade replacement expedient to efficient operation. Operability of the Bacon knife may be further affected by wear of the drive shaft such that the shaft itself in effect reciprocates in its mount. Such play of the shaft within its mount, especially when taken together with the play of the cam within the blade opening, can appreciably reduce stroke length and hence the cutting efficiency of the knife. Such wear may require early shaft replacement. While convenient replacement of worn parts is an advantage of the Bacon knife, such replacement should, of course, be minimized to reduce the cost of replacement parts and to avoid the loss of productivity associated with knife maintenance.